17 de julio de 2024

Illustrations of sexual dimorphism in Hippopotamus amphibius









Adult females:




Adult males:









Publicado el 17 de julio de 2024 a las 11:44 PM por milewski milewski | 1 comentario | Deja un comentario

Why is there no such thing as a migratory carnivore?

Publicado el 17 de julio de 2024 a las 01:46 AM por milewski milewski | 0 comentarios | Deja un comentario

13 de julio de 2024

12 de julio de 2024

Colouration of Gazella pelzelni

I have adopted Gazella pelzelni as a standard, for my studies of adaptive colouration in Gazella and Eudorcas.


I disregard all hues, focussing only on pale/dark differentiations.

I estimate tone (from pale to dark) on a scale of 1-10. 1= white, 10= black, and thus 5= medium 'grey'.

All numbers in this Post refer to this tonal scale.

'dark' flank-band up to 7

'pale' flank-band about 3.5

dorsal panel 4 up to 5

ischial stripe (vertical) 5

neck about 4

ventral haunch about 4

outer surface of lower foreleg 4
posterior surface of lower foreleg 2
outer surface of lower hindleg 3.5-4
outer surface of upper foreleg at least 5

shoulder about 5

malar stripe up to 8

chin 1

pale facial stripe, medial to eye 1
pale facial stripe, on side of rostrum 2-3

forehead up to 6

cheek about 3

nasal about 4

tail 9

root of tail 7

Dark rostral spot minimal in adult male, present in adult female



Publicado el 12 de julio de 2024 a las 09:50 PM por milewski milewski | 1 comentario | Deja un comentario

09 de julio de 2024

A new term for an important biological phenomenon: introducing 'secromorphosis' as categorically distinct from metamorphosis

@tonyrebelo @jeremygilmore @ludwig_muller @jwidness @thebeachcomber @lupoli_roland @wongun @nomolosx @mpintar @kgrebennikov @lehelind @andreyperaza @hemala_vladimir @hopperdude215 @nmhernandez @dan_johnson @psyllidhipster @gernotkunz @beetle_mch @mydadguyfieri @lrubio7 @bnormark @darwinnie @rjpretor @entomike @mathieu_h @benwx @elytrid @megachile @extasiptera @tmvdh @easmeds @pfau_tarleton @szucsich @teuthis

Before reading this Post, please watch https://www.youtube.com/watch?v=3EVLJChVV48.

Everyone knows that

However, there is another process whereby the bodies of arthropods are radically modified. This deserves a term of its own: secromorphosis.

[As a necessary digression, please note a terminological quirk. The biological adjective derived from the noun 'metamorphosis' is 'metabolous', not 'metamorphic'. Likewise, those derived from holometamorphosis and hemimetamorphosis are respectively holometabolous and hemimetabolous. In accordance, the adjective derived from my new term - albeit unsatisfactory owing to some ambiguity with metabolism - would be secrobolous, not secromorphic.]

In metamorphosis,

By contrast, in secromorphosis, the transformation of the body - which can be extreme (https://lostcoastoutpost.com/nature/5938/ and https://australian.museum/learn/animals/insects/giant-female-scale-insects-and-bird-of-paradise-flies/ and https://www.ecoorganicgarden.com.au/problem-solver/how-to-control-lerps/ and https://www.dpi.nsw.gov.au/agriculture/horticulture/citrus/content/insects-diseases-disorders-and-biosecurity/insect-pest-factsheets/long-tailed-mealy-bug#:~:text=Description&text=Adults%20are%203%E2%80%934%20mm,a%202%E2%80%933%20week%20period. and https://www.projectnoah.org/spottings/135616016 and https://www.projectnoah.org/spottings/21883009 and https://upload.wikimedia.org/wikipedia/commons/a/af/Ceroplastes_cirripediformis.jpg and https://upload.wikimedia.org/wikipedia/commons/3/30/Red_lerps_austrochardia_acaciae.jpg) - is achieved by means of secretion.


The body-parts secreted - '3-D printed', as it were, by glands - consist mainly of various organic compounds (https://www.perplexity.ai/search/what-is-the-overall-term-for-m-vzBxp5QiQsiuxJqs.GQVnQ), including both

These secreted structures, which can be substantial relative to body size, are non-living, even though they form part of a living body.

It is true that important components - particularly the exoskeleton and wing-membranes - of the body in metabolous arthropods consist of dead tissue. However, there is a categorical distinction between once-living (i.e. metabolising, containing DNA, and undergoing cell-division), now-dead materials on one hand, and materials that have never been alive on the other.

The relevant body-parts of secromorphic insects, particularly the waxy filaments, shields, and lattices secreted by sap-sucking sternorrhynchan hemipterans (https://en.wikipedia.org/wiki/Sternorrhyncha), fall into the latter category.

Everyone knows that the bodies of arthropods contain non-living components, particularly exoskeletons made of chitin (in some cases reinforced by calcium carbonate).

However, all chitinous body-parts are derived from cell-walls. In other words, they originate as living tissues that have then died and become indurated.

The crucial distinction is that the components produced in secromorphosis are not aptly described as dead. This is because - like secretions as a category - they were not metabolically active in the first place.

Within Hemiptera, the trend is for an inverse correlation between chitinousness and waxiness. Heteroptera rely on chitin, whereas Sternorrhyncha tend to have minimal exoskeletons, relying instead on wax. Achenorrhyncha are intermediate in this respect.

As far as I know,

  • all secrobolous insects are also hemimetabolous, i.e. they show hemimetamorphosis in the form of an ontogenetic series of nymphs culminating in an adult, and
  • most or all secrobolous insects fall within Hemiptera (https://en.wikipedia.org/wiki/Hemiptera).

It follows that most or all secrobolous insects are sap-suckers, foraging mainly on the fluid contents of phloem (https://en.wikipedia.org/wiki/Phloem).

This leads to a strange realisation: that hemipterans manifest two aspects of a rapid throughput of carbon and hydrogen, and to some extent oxygen.

Sap-sucking hemipterans take in much superfluous sugar as they filter dilute fluids for their content of nitrogen and mineral nutrients. As part of this process, they exude the energy-content of most of this sugar, whether as

There is a kind of congruence in the fact that sap-sucking hemipterans

  • take in large quantities of energy superfluous to metabolism, and
  • subsequently exude (3-D print, https://en.wikipedia.org/wiki/3D_printing) the energy-containing substances, in modified form, for various purposes.

In the case of most secrobolous hemipterans (belonging to a bewilderingly large number of families in two suborders and many superfamilies):
sugar in, wax out.

And wax can be so much more durable/imperishable than sugars - indeed, almost as durable as chitin in the case of small insects - that it can effectively constitute a large proportion of the body (albeit extraneous to the tissues, both living and dead).

In the past, most insects have been categorised as either holometabolous or hemimetabolous. With the realisation that many sternorrhynchan and some auchenorrhynchan hemipterans are secrobolous, how should woolly aphids, lerp psyllids, wax scalebugs, etc., be best categorised?

Relevant to this question is the observation that the waxy secretions are best-developed in nymphs in some clades of hemipterans, vs in adults in other clades. In some families, even the eggs are invested in waxy filaments (https://www.perplexity.ai/search/in-which-sternorrhynchan-and-a-SD3Y5dGdRjOM_qDIWNoKZw).

In extreme cases, an adult the size of a small fly (https://upload.wikimedia.org/wikipedia/commons/8/89/Bird_of_Paradise_Fly.jpg) may possess a waxy 'tail', consisting of filaments up to 7.5 cm long (https://www.inaturalist.org/taxa/706751-Callipappus-australis and https://www.perplexity.ai/search/which-sternorrhynchan-hemipter-b8qjNcwDQvOh4qos8rQxSQ).

Given that the secretions correspond incongruently to growth-stages, across the various clades of hemipterans, I would argue that the categorisation of certain taxa as secrobolous is more relevant/informative than their categorisation as hemimetabolous.

Here is a question corollary to this topic:
Does any insect secrete chitin, which is a polysaccharide, viz. a polymer of sugar (https://www.perplexity.ai/search/is-any-arthropod-known-to-secr-xA81XDKuT4ykAEVrVpQxaA)?


















Publicado el 09 de julio de 2024 a las 09:23 PM por milewski milewski | 14 comentarios | Deja un comentario

Is the Australian mole (Notoryctes) a supermole?

The marsupial mole (Notoryctes, https://en.wikipedia.org/wiki/Marsupial_mole and https://www.abc.net.au/news/2023-06-17/elusive-marsupial-mole-spotted-uluru-swims-in-sand/102482890 and https://books.google.com.au/books?hl=en&lr=&id=5IqhZoTEF10C&oi=fnd&pg=PA464&dq=Marsupial+mole&ots=KQKu9dlYtl&sig=6N4ZqycOmL5In2yGuKzJVJ7tIF8&redir_esc=y#v=onepage&q=Marsupial%20mole&f=false) superficially resembles placental moles, despite being unrelated to them.

This is one of the most striking examples known of evolutionary convergence (https://en.wikipedia.org/wiki/Convergent_evolution).

However, the marsupial mole does not merely combine the presence of a pouch with the disappearance of eyes and ears.

As research gradually uncovers the details about the only Australian mole, what is emerging is that this is more than a lookalike.

The marsupial mole may indeed be the quintessential mole. It not only matches, but possibly surpasses, the adaptive extremes shown by subterranean mammals on other continents.

The marsupial mole has a large, bare pad on the head (https://www.bbc.com/news/world-australia-68720246). This has not been studied, but appears to be a blunt instrument of subterranean locomotion.

Unlike other moles, the marsupial mole has fused vertebrae in the neck, which presumably allows great pressure to be placed on the head as a ramrod.

Typical moles (Talpidae, https://en.wikipedia.org/wiki/Talpidae) lack a burrowing organ on the head, instead having pointed muzzles as soft as those of shrews.

Golden moles (Chrysochloridae, https://en.wikipedia.org/wiki/Golden_mole), the moles of Africa, have a tough nose used as a wedge (https://afrotheria.net/golden-moles/photos.php). However, the bare pad is far too small to extend to the forehead.

If typical moles and golden moles are not as extremely adapted to butting through the earth as is the marsupial mole, this may be because they repeatedly commute along tunnels once they have constructed them.

The marsupial mole appears to have no open tunnels, instead forcing its way afresh through every centimetre of earth in the course of its locomotion (https://www.publish.csiro.au/am/AM13015).

In this sense, the marsupial mole may be the ultimate subterranean mammal.

A failure to construct tunnels explains why, unlike other moles, the marsupial mole does not make molehills.

The Namib golden mole (Eremitalpa, https://en.wikipedia.org/wiki/Grant%27s_golden_mole) also lacks molehills. However, it differs from the marsupial mole by depending partly on swimming through the relatively loose sand at the surface of dunes. They maintain their body temperatures, remain active and warm even under the snows of winter, and reproduce relatively rapidly.

The forefoot of the marsupial mole is extreme, since the claws form a vertical spade (https://www.abc.net.au/news/2024-04-07/-northern-marsupial-mole-kakarratul-sighted-/103662744).

Typical moles have different forefeet, essentially broad paws projecting sideways as if from the neck (https://www.sci.news/biology/european-moles-sand-08805.html and https://www.parchilazio.it/cammino_naturale_dei_parchi-schede-7288-animalisulcammino_la_talpa_europea and https://nature.guide/card.aspx?lang=en&id=579), and used for raking relatively crumbly soil sideways.

Whereas the claws of typical moles move beside the body, those of the marsupial mole cleave the sand downwards, in front of the body.

Golden moles have pick-like claws on digits number 2 and 3 of the forefoot, held horizontal instead of vertical.

The marsupial mole has similar claws in digits 2 and 3. However, it has an additional, particularly large claw on digit 4, which forms the main blade of the articulated spade.

Typical moles lack external ears, but retain internal ear bones capable of hearing low-pitched vibrations underground.

The marsupial mole is unique among moles, because its entire ear is degenerate. The extremely small size of its internal ear bones suggest that the marsupial mole is nearly deaf as well as blind (https://www.mdpi.com/2073-4425/14/11/2018 and https://www.pnas.org/doi/abs/10.1073/pnas.94.25.13754).

This contrasts with the golden moles, in some of which the size of the ear bones exceeds that of surface-dwelling mammals, proportional to body size.

The tail of the marsupial mole is odd, inviting further study. Its appearance suggests that the tail may be used as a prop, allowing extra pressure to be placed on the head and claws. If so, the use of the tail in digging is unprecedented among subterranean mammals. No-one has yet a found a way to observe the marsupial mole in action underground.

The marsupial mole differs in habitat from other moles. It is widespread in, and apparently restricted to, hummock grassland (https://www.anbg.gov.au/photo/vegetation/hummock-grasslands.html and https://www.publish.csiro.au/am/AM00115).

This is a peculiar type of 'desert' restricted to Australia, sandy and dry but vegetated (https://www.inaturalist.org/posts/58175-the-australian-empty-quarter-epitome-of-a-nutrient-desert#).

Failure of Europeans and domestic animals to exploit hummock grassland owes more to this land's extreme nutrient-poverty than its aridity (https://www.inaturalist.org/posts/58175-the-australian-empty-quarter-epitome-of-a-nutrient-desert).

This semi-desert is even less fertile than the Sahara, so that 20% of Australia remains deserted to this day, despite the availability of groundwater in boreholes.

The main cover consists of grasses (Triodia, https://en.wikipedia.org/wiki/Triodia_scariosa) more spiny, unpalatable, and flammable than any common grass on other continents.

Although sand is extensive on the other southern continents, no mole lives in vegetated sand under dry conditions far inland.

Typical moles are widespread in the Northern Hemisphere (https://people.wku.edu/charles.smith/faunmaps/Talpidae.htm). However, they depend on the organic, loamy soils of deciduous woodlands.

Golden moles in Africa extend to sandy substrates in coastal areas. However, they are absent from the only habitats comparable to that of the marsupial mole: the Kalahari in southern Africa (https://en.wikipedia.org/wiki/Kalahari_Desert), and sandy parts of the Sahel at the edge if the Sahara (https://en.wikipedia.org/wiki/Sahel).

There are no moles today in central and South America, although fossil moles related to armadillos have been excavated. The most mole-like species alive now is the lesser fairy armadillo (Chlamyphorus truncatus, https://www.inaturalist.org/taxa/47097-Chlamyphorus-truncatus), restricted to a small area of sandy soil in semi-arid Argentina (https://upload.wikimedia.org/wikipedia/commons/2/29/Lesser_Fairy_Armadillo_area.png).

What little is known of the diet of the marsupial mole suggests an unusual reliance on insect larvae (https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.2011.00889.x). I suspect that the tropical species of marsupial mole (Notoryctes caurinus) may depend partly on the brood (eggs, larvae, pupae) of ants, which it raids by burrowing from one subterranean ant nest to another.

By comparison:

Subterranean mammals have to devote most of their food energy to the strenuous work of burrowing. However, they save energy when resting, because the underground environment has a comfortable temperature and a poor supply of oxygen.

In addition, protection from predators means that subterranean mammals do not need to devote much energy to reproduction.

The resting metabolism of golden moles and armadillos is even slower than that of most marsupials. However, further research may show that the reproduction of the marsupial mole is particularly slow.

If so, it is possible that the marsupial mole devotes less of its energy to offspring, and more of its energy to locomotion, than any other subterranean mammal. Typical moles are different, because they have a rich supply of earthworms in ventilated tunnels.

The marsupial mole stretches our concept of the genetic plasticity of marsupials. It may also be a 'supermole' in stretching adaptive limits beyond those of placental moles. The broad hard organs of its head and forefeet, and to a lesser degree hindfeet and tail, equip it to burrow afresh to each meal, despite the poor food to be found in a habitat lacking both nutrients and water.

Genetic constraints and geographical isolation therefore fail to explain the absence of other body forms (equivalent to bears, pigs, primates, otters, cats, and ruminants) in the indigenous fauna of Australia.

In particular, the lack of mole-rats in Australasia is unlikely to be an accident of history. All other continents (including central and South America) have rodents resembling gophers, derived from a total of eight families which have independently undergone reduction of eyes, ears, tails, and resting metabolic rates (https://www.jstor.org/stable/2096793).

However, the supply of edible tubers appears to be smaller in hummock grassland than in the Kalahari. Possibly, mole-rats failed to evolve in Australia because of a lack of suitable tubers as food.

Publicado el 09 de julio de 2024 a las 08:36 AM por milewski milewski | 16 comentarios | Deja un comentario

07 de julio de 2024

The ecological and biogeographical significance of Prodotiscus regulus, an anthropogenic addition to the avifauna of Cape Town, South Africa

@tonyrebelo @ludwig_muller @jeremygilmore @vynbos @lukedowney @carasylvia @moxcalvitiumtorgos @rion_c @johnnybirder @theoutdoorman102 @surfinbird @justinponder2505 @simontonge @nwatinyoka @richardgill @adamwelz @boerseun86 @luke_goddard @zroskoph @kristaoswald @gareth_bain @wikus_burger @wingate @joelradue @colin25 @lindeq @the_bush_fundi @gigilaidler @lindalakeside @manatok @christiaan_viljoen @ekmes @ianrijsdijk @markheystek

Prodotiscus regulus (https://www.inaturalist.org/taxa/17591-Prodotiscus-regulus) is

The aim of this Post is to explain how P. regulus has come to be the only species of bird in the Cape Floristic Region (https://en.wikipedia.org/wiki/Cape_Floristic_Region) that specialises dietarily on the exudates of sap-sucking hemipteran insects (https://tcimag.tcia.org/training/sap-sucking-insects-how-they-feed-and-the-damage-they-cause/).

Like all members of its family (https://www.sciencedirect.com/science/article/abs/pii/S1095643302001307#:~:text=Birds%20ate%20significantly%20more%20new,transit%20time%20of%20256%20min. and https://pubmed.ncbi.nlm.nih.gov/12160878/), P. regulus can digest wax (https://en.wikipedia.org/wiki/Wax), as a major source of metabolic energy.

This is remarkable, because wax is

Before European arrival, there was no niche for P. regulus in the southwestern part of South Africa.

This is mainly because

Exudates of sap-sucking hemipterans are mainly of two kinds, viz.

Europeans introduced several spp. of Acacia (https://en.wikipedia.org/wiki/Acacia) from Australia to the Cape Floristic Region.

These shrubs and trees have proven to be so ecologically vigorous in their new environment that they are regarded as invasive (https://www.cabidigitallibrary.org/doi/10.1079/9781800622197.0026).

Also introduced - albeit mainly inadvertently - from various parts of the world were several hemipterans capable of sucking the sap of these acacias (https://www.perplexity.ai/search/australian-spp-of-acacia-have-5WdSTOFwQHK06p4MSWQYiw and https://en.wikipedia.org/wiki/Icerya_purchasi).

Now, for the first time in and near Cape Town (https://en.wikipedia.org/wiki/Cape_Town), there was a plentiful source of sap-sucking hemipterans and their exudates, as potential food for arboreal birds indigenous to South Africa.

In the case of honeydew, the main indigenous bird that seems to have benefited is Zosterops, a genus observed elsewhere in Africa to forage side-by-side with P. regulus (Friedmann 1955, https://repository.si.edu/handle/10088/10101 and https://scholar.google.com/citations?user=62DqSSUAAAAJ&hl=en).

Zosterops (https://www.inaturalist.org/observations?place_id=6986&taxon_id=17439&view=species) is a small-bodied passerine with the odd combination of a short, thin beak and a brush-tipped tongue. This allows it to lap up the newly-provided honeydew, in addition to its original staple diet of fleshy fruit-pulp (and -juice) and insects (https://www.researchgate.net/publication/249439178_Summer_and_winter_diet_of_the_Cape_white-eye_Zosterops_pallidus_in_South_African_grassland#:~:text=...-,The%20Cape%20white%2Deye%20is%20described%20as%20a%20generalist%20feeder,their%20diet%20(Kopij%202004)%20.).

However, this hardly changed Zosterops biogeographically, because it had been present in the Cape Floristic Region in the first place.

In the case of the waxy exudates, the only indigenous birds that might benefit were Indicatoridae.

As many as three spp. of Indicator may have been indigenous to the Cape Floristic Region, viz.

However, this genus is adapted to take wax from the nests of Hymenoptera, not from the exudates of hemipterans. This preference may be explained partly by the fact that Indicator is larger-bodied than Prodotiscus (https://en.wikipedia.org/wiki/Honeyguide).

Instead, what seems to have happened is that a small-bodied species, viz. P. regulus, entered the Cape Floristic Region for the first time during the twentieth century. This spontaneous recruitment filled the newly-provided niche.

There was no competition between P. regulus and Zosterops, because

  • the former is hardly able to ingest honeydew, and
  • the latter is unable to digest wax.

Honeydew is not utilised by Indicatoridae, despite

The inutility of honeydew for Indicatoridae, including P. regulus, seems to be because they

What has arisen is something biogeographically remarkable, and overlooked by naturalists despite the avifauna of Cape Town, and the Cape Floristic Region, being intensively studied.

This is that

Publicado el 07 de julio de 2024 a las 03:45 AM por milewski milewski | 9 comentarios | Deja un comentario

04 de julio de 2024

A puzzling lack of honeydew-producing hemipteran insects in the Cape Floristic Region of South Africa

@tonyrebelo @jeremygilmore @ludwig_muller @rjpretor @psyllidhipster @wongun @fabienpiednoir @bnormark @nomolosx @vynbos @peterslingsby @erincpow

Honeydew (https://en.wikipedia.org/wiki/Honeydew_(secretion) and https://www.sciencedirect.com/science/article/abs/pii/B9780123741448001314) is produced by various families of sap-sucking hemipterans in the suborders

The main sternorrhynchan families involved are

(For auchenorrhynchan families see https://www.inaturalist.org/posts/96522-a-puzzling-lack-of-honeydew-producing-hemipteran-insects-in-the-cape-floristic-region-of-south-africa#activity_comment_ad4868eb-6860-4458-b914-3a0659762ec5.)

Honeydew-producing hemipterans are common and diverse in several ecosystems that are

  • dominated by evergreen, woody plants,
  • nutrient-poor (particularly w.r.t. phosphorus and zinc), and
  • prone to wildfire.

The following ecosystems are particularly relevant.

Boreal forest (https://en.wikipedia.org/wiki/Taiga):

The incidence of sap-sucking hemipterans is summarised in https://www.perplexity.ai/search/which-are-the-main-sap-sucking-EM7jj6ifR_y2Oe2cmqAO_Q.

Eucalypt-dominated vegetation in Australia:


Honeydew is so common in eucalypt-dominated vegetation that honeyeaters (Meliphagidae) often eat this substance in place of nectar (https://www.publish.csiro.au/mu/mu9800213).

Kwongan in Australia:



At least one family of honeydew-producing hemipterans, viz. Pseudococcidae, is noted for its diversity in the floristically-rich southwestern region of Western Australia (https://www.perplexity.ai/search/which-honeydew-producing-sap-s-4PdFXzbnSziooSPIbxUcYw and https://www.inaturalist.org/posts/96522-a-puzzling-lack-of-honeydew-producing-hemipteran-insects-in-the-cape-floristic-region-of-south-africa#activity_comment_4fdf2d80-eeb1-404c-9aac-4f7225c93fe9).

Cerrado in South America:



Now, the fynbos biome of South Africa is nutrient-poor and fire-prone (https://en.wikipedia.org/wiki/Fynbos and https://www.sciencedirect.com/science/article/pii/S0254629914002117).

Therefore, we might expect fynbos - and the Cape Floristic Region (https://en.wikipedia.org/wiki/Cape_Floristic_Region) in general - to feature honeydew-producing hemipterans.

However, I have found hardly any information on this in the literature (https://www.perplexity.ai/search/anoplolepis-tends-sap-sucking-tebUgY.xQMuD36uISyJYNg and https://www.perplexity.ai/search/in-southern-africa-which-indig-yHiltTzwTESZjCLocBN0aA and https://www.perplexity.ai/search/in-southern-africa-which-are-t-Yajw5J0hT0GAFWFTNu8Zug and https://www.perplexity.ai/search/is-there-any-literature-on-hon-BNXvvEnVQAS_Gi41Ja.GyA).

Nectariniidae (https://www.perplexity.ai/search/is-any-member-of-nectariniidae-AArpb.xdSre4mi7wy.IwnA) and Promeropidae (https://www.perplexity.ai/search/has-promerops-ever-been-record-WC3kBuvWSGCnV5Nz5jg6hw), common in fynbos, have not been recorded eating honeydew. In this way, they differ from their approximate ecological counterparts, viz. Meliphagidae, in Australia.

It may be relevant that European heathland, superficially similar to ericoid fynbos (https://en.wikipedia.org/wiki/Ericoid), also seems poorly-documented for honeydew-producing hemipterans (https://www.perplexity.ai/search/which-are-the-main-honeydew-pr-N0CYxtJtRMqg9Z9zB2sjRw).

This leaves us with the following question:

Is the dearth of information on honeydew-producing hemipterans in fynbos because of a gap in coverage, or does it reflect a real poverty, indicating some basic and poorly-understood aspect of the functions of the ecosystem?


The following are notes in the biogeography of various clades of honeydew-producing hemipterans.


In the Northern Hemisphere, Aphididae are a major family producing honeydew. In Australia, indigenous Aphididae are ecologically unimportant (https://academic.oup.com/aesa/article/96/2/107/27979). Here,their place is taken by Psyllidae and Pseudococcidae.

In New Zealand, the main indigenous sternorrhynchans that produce honeydew are Margarodidae, Coccidae, and Aphididae.









Publicado el 04 de julio de 2024 a las 09:54 AM por milewski milewski | 21 comentarios | Deja un comentario

03 de julio de 2024

The real - and disappointing - nature of the red wolf ('Canis rufus')

@ptexis @matthewinabinett @tonyrebelo @jeremygilmore @dinofelis @beartracker @paradoxornithidae @adamwelz @karoopixie @leytonjfreid @thebeachcomber @maxallen

There are several 'dogs not barking' in the real nature of the red wolf (Canis rufus, https://en.wikipedia.org/wiki/Red_wolf) of southeastern North America.

And these oversights offer insights into the values of nature conservation, the scientific method and - indeed - human psychology.

Everyone knows that

However, what is not appreciated - because it is too dispiriting to contemplate - is that the red wolf is probably also profoundly hybridised with the domestic dog (Canis familiaris).

If it were accepted that the real nature of the red wolf is a three-way hybrid, among domestic dog, coyote, and wolf, then it might seem unjustifiable to spend so much time, energy, and money on the conservation of what cannot be argued to be a wild animal.

However, such acceptance has yet to arrive. And this 'blind spot' has amounted to cognitive dissonance, and a failure of scientific objectivity.

Dear readers, please consider:
How could the domestic dog not have been involved, in an important way, in the ancestry of the red wolf?

The answer is that it must be assumed to have been involved. There are two planks in my rationale, the first based on a logic of consistency, and the second pointing out a 'sin of omission'.


Taxonomists seem unanimous in the view that the wolf is the main ancestor of the domestic dog. This implies an acceptance - that should likewise be unanimous - that the introduction of the domestic dog to North America led to hybridisation with the wolf.

Because this introduction occurred at the end of the Pleistocene (https://www.perplexity.ai/search/when-was-the-domestic-dog-intr-KGnFbfn4TT6KfeOsMkAZuQ),

All-dark individuals, in populations of the wolf in both North America and Eurasia, particularly signify a history of hybridisation with the domestic dog (https://en.wikipedia.org/wiki/Black_wolf and https://www.indiatimes.com/news/india/black-wolf-photographed-for-the-first-time-in-india-here-is-why-it-is-concerning-631944.html). Such individuals have occurred likewise in the red wolf, indicating that it, too, is introgressed.


The various genetic analyses of the red wolf have been 'deafeningly silent' on the question of how important the domestic dog has been in the ancestry of 'Canis rufus' (https://www.perplexity.ai/search/various-studies-have-been-publ-fqScDp3oQ0O7JkXBrzGlag).

This indicates cognitive dissonance (https://en.wikipedia.org/wiki/Cognitive_dissonance), because

  • everyone has assumed that the domestic dog is, in a sense, a non-wild form of mainly the wolf, and yet
  • nobody has assumed that the red wolf may, by the same token, be mainly a feral form of the domestic dog.

Now, there is an additional aspect, which would be a 'nail in the coffin' for any notion that the red wolf deserves to be conserved as a wild animal.

This is that

Several aspects of the colouration of the red wolf indicate affinity with 'Canis rubronegrus', rather than either the wolf or the coyote. These include

I suggest, therefore, that

Either way, attempts to bring the red wolf back from the brink may have been an expensive mistake.

It is one thing to accept that, in a genus as phylogenetically fluid as Canis, it is somewhat arbitrary whether any population qualifies as a particular species (as opposed to a hybrid).

However, it is another thing to pretend that a 'coywolf' is worth conserving, in a region of North America where one of the components, namely the coyote, was not even indigenous in the first place.

It is another thing again to 'shoehorn', into the concept of a valid species, an entity that is two-steps downgraded (latrans X lupus X lupus-familiaris) from an original species.

And it would be yet another grade of delusion, beyond the above three grades, to ignore that the hybridisation involved not two, but three original wild spp. (latrans X lupus X rubronegrus-familiaris).

Is the reality not that, in a region altered anthropogenically for ten millennia, and altered by Europeans for 500 years (https://www.perplexity.ai/search/when-did-europeans-first-settl-bxkgLugnQbGc.NulizD5lQ), any species of truly wild Canis is long-lost?

And is the likelihood not that, in continuing to avoid coming to terms with this loss, we conservationists are undermining our own effectiveness?

Publicado el 03 de julio de 2024 a las 06:55 PM por milewski milewski | 13 comentarios | Deja un comentario

30 de junio de 2024

Data on braininess in mammals, part 8, including confusion about the encephalisation quotient of Cavia porcellus

@tonyrebelo @jeremygilmore @ludwig_muller @christiaan_viljoen

...continued from https://www.inaturalist.org/journal/milewski/96318-data-on-braininess-in-mammals-part-7-ontogenetic-progression-of-brain-mass-in-ruminants-from-birth-to-adulthood#

In this Post, I collate and discuss valuable data on encephalisation quotients (EQ) in three articles in the literature, viz.

  • Shigeno et al. (2017),
  • Papini (2008), and
  • Herculano-Houzel (2007).

This information covers a wide range of mammals. However, most noteworthy are certain rodents, in which I question the validity of the data.

A reminder to readers:

  • EQ indicates braininess,
  • by definition, the average mammal has EQ=1.0, and
  • values >1.0 indicate braininess exceeding expectations for a mammal, whereas values <1.0 indicate the opposite.

Within each of the three sets of data, I list the various spp. in order of decreasing EQ.

SHIGENO ET AL. (2017, https://link.springer.com/chapter/10.1007/978-4-431-56469-0_19)

Listed in order of decreasing EQ:

Canis 1.18
Felis 1.0
Zaglossus 0.87
Ornithorhynchus 0.83
Dasyurus 0.72
Monodelphis 0.68
Vombatus 0.64
Procavia 0.58
Dasypus 0.41
Manis 0.39
Didelphis 0.33
Trichechus 1.05 (probably erroneous, see https://www.perplexity.ai/search/what-is-the-encephalisation-qu-h5on8FyXQ8.UNR9oFtTyuA)

My commentary:

The two monotremes (https://en.wikipedia.org/wiki/Monotreme) are 'primitive' among mammals. For example, Ornithorhynchus has body temperatures 5-34 degrees Celsius, usually about 31 degrees Celsius - compared to 37 degrees Celsius in Homo sapiens.

However, monotremes are surprisingly brainy. This seems correlated with their extreme electrosensitivity (https://www.researchgate.net/publication/13087040_Electroreception_in_Monotremes).

The monotreme Tachyglossus aculeatus has the largest prefrontal cortex, relative to body mass, of any mammal. This contributes perhaps up to 50% of the volume of the cerebral cortex, compared to about 29% in Homo sapiens (https://www.perplexity.ai/search/what-percentage-of-human-brain-mI1HODdqQMaI.m6jc_5oMw and https://pubmed.ncbi.nlm.nih.gov/3427409/).

The opossum genus Didelphis is decephalised even among marsupials. This correlates with extreme fecundity (in the sense of many newborns per litter) and short lifespan.

PAPINI (2008,

Listed in order of decreasing EQ:

Homo sapiens 7.33
Phocoena phocoena 4.90
Cebus capucinus 3.40
Tursiops truncatus 3.23
Vulpes vulpes 1.89
Globicephala melas 1.70
Equus zebra 1.70
Lemur catta 1.45
Desmodus rotundus 1.23
Atherurus africanus 1.19
Choloepus hoffmanni 1.09
Equus caballus 1.07
Dasyurus sp. 1.05
Pteropus 'geddeiri' 0.95
Ornithorhynchus anatinus 0.94
Ursus arctos 0.91
Tapirus bairdii 0.87
Myrmecophaga tridactyla 0.81
Rattus norvegicus (laboratory, albino) 0.79
Neomys fodiens 0.75
Tachyglossus aculeatus 0.72
Panthera leo 0.70
Hydrochoerus hydrochaeris 0.68
Myotis lucifugus 0.52
Suncus murinus 0.48
Macropus giganteus 0.47
Didelphis marsupialis 0.46
Setifer setosus 0.45
Dasypus novemcinctus 0.37
Bison bison 0.35
Hippopotamus amphibius 0.33
Sus scrofa 0.27

My commentary:

I suspect that, in the case of Bison bison, the value

  • refers to mature males, and
  • would be considerably greater (>0.6?) in adult females.

The value for Atherurus africanus is surprisingly great for a non-sciurid rodent. In the case of the 'edentate' Choloepus hoffmanni, I find the magnitude of the value to be incredible (possibly erroneous?).

The converse applies somewhat to Sus scrofa, the value for which seems too small (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0157378).

The contrast in encephalisation is noteworthy between two microchiropteran bats (https://en.wikipedia.org/wiki/Microbat), namely Desmodus rotundus and Myotis lucifugus.

HERCULANO-HOUZEL (2007, https://d1wqtxts1xzle7.cloudfront.net/48887613/pdf-libre.pdf?1474043818=&response-content-disposition=inline%3B+filename%3DEncephalization_Neuronal_Excess_and_Neur.pdf&Expires=1719801754&Signature=fpHt-S-W9Z5opc4EEnbjOxfR4CSYsB7Aab-X1A~71YFdVlgfNnGEWCrYoFGFki~SrS1UAjHBOuj0iJWi719jy9wNRi7iaQYtW27f864iDohiBoSvcv-mMXVmlUJYUiT58s6rraZWQUM8a~5cBRZHKYLaJZkYTbbbTgkxoiz~bctcjF7hG9CYmzVj3rVgIXno7guL2tB15NkSjXiVhmvmp2R~LgJU~cARUVOSmIfrLc6FZrVTxf8Y1cGCLz30wrkRiJ3p4rNsqfFssqdAOhRrx5E1dk6xL6mKnqjk41NoRJu6EoUNzoksLLN4O5rLgdwlotiGGo~RlgRtvsJwaWxPYQ__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA)

Listed in order of decreasing EQ:

Cavia porcellus (n=2) body mass mean 311.0 g, brain mass mean 3.759 g, encephalisation quotient 1.711

Dasyprocta sp. (species not stated) (n=3) body mass mean 2843.3 g, brain mass mean 18.365 g, encephalisation quotient 1.519

Mus musculus (n=4) body mass mean 40.4 g, brain mass mean 0.416 g, encephalisation quotient 0.949

Rattus norvegicus (n=4) body mass mean 315.1 g, brain mass mean 1.802 g, encephalisation quotient 0.828

Cricetus cricetus (presumably; scientific name not stated) (n=2) body mass mean 168.1 g, brain mass mean 1.020 g, encephalisation quotient 0.745

Hydrochoerus hydrochaeris (n=2) body mass mean 47500.0 g, brain mass mean 76.036 g, encephalisation quotient 0.71

My commentary:

The encephalisation quotients for Rattus norvegicus and Hydrochoerus hydrochaeris agree with those of Papini (2008), shown above within this Post.

However, the encephalisation quotients found here by Herculano-Houzel (2007) differ surprisingly from those elsewhere in the literature. In the case of Cavia porcellus, I find the value (EQ=1.7) to be incredible.

For comparison, Steinhausen et al. (2016) found the following encephalisation quotients for the same spp. (see https://www.inaturalist.org/journal/milewski/96127-data-on-braininess-in-mammals-part-5#) :

Cavia porcellus 0.40
Dasyprocta sp. 0.91
Mus musculus 0.53
Rattus norvegicus 0.45
Cricetus cricetus -
Hydrochoerus hydrochaeris 0.67

In all cases except the extremely large-bodied H. hydrochaeris, the encephalisation quotients of Herculano-Houzel (2007) greatly exceed those of Steinhausen et al. (2016).

This suggests that

  • different mathematical methods were used, allometrically, and
  • those of Herculano-Houzel (2007) make the more sense, in terms of a correlation between braininess and intelligent behaviour.

However, in the case of Cavia porcellus, the disparity is so extreme that it is Herculano-Houzel (2007) who seems to have made some sort of basic error of exaggeration.

The difference in encephalisation quotient for C. porcellus, between the two references, is more than fourfold. A value of 1.7 makes no sense, because

Perhaps indicating a basic error of exaggeration of brain size in C. porcellus is the following quote from page 1286 of Herculano-Houzel (2007): "the agouti, which has a similar EQ to the guinea pig, does have a much larger number of 'extra neurons'...than the guinea pig...despite the smaller neuronal density found in larger rodent brains."

In possible resolution if this anomaly, please see Pirlot and Bee De Speroni (2009, https://www.degruyter.com/document/doi/10.1515/mamm.1987.51.2.305/html).

Also see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8200626/.

Publicado el 30 de junio de 2024 a las 10:23 PM por milewski milewski | 2 comentarios | Deja un comentario